Geometrical transformation of images

Geometrical transformation of images

close all

clear all

a=imread('cameraman.tif');

b=imrotate(a,-30,'bilinear','crop');

imshow(a);

figure,imshow(b);

Image Scaling

b=imrotate(a,-3,'bilinear','crop');

>> imshow(a);

>> figure,imshow(b);

>> [m,n]=size(a);

>> i=0.5;

>> c=imresize(a,[m*i n/i]);

>> figure,imshow(c);

Interpolation

a=imread('cameraman.tif');

[x y]=meshgrid(1:256,1:256);

t=pi/4;

for i=1:256

    for j=1:256

x1(i,j)=cos(t)*x(i,j)+sin(t)*y(i,j);

y1(i,j)=sin(t)*x(i,j)+cos(t)*y(i,j);

end;

end

z=interp2(x,y,a,x1,y1,'cubic');

Sampling rate:

f=ind2gray(a,gray(256));

>> f1=imresize(f,0.2);

>> figure,imshow(f1);

>>  f2=imresize(f1,5);

>> figure,imshow(f2);

imhist(f);

Add noise to an image and median filter is used to remove the noise

f=ind2gray(a,gray(256));

f1=imnoise(f,'salt & pepper',0.05);

f2=medfilt2(f1,[3 3]);

figure; imshow(f);

figure; imshow(f1);

figure; imshow(f2);